1. Field
This application relates to air filters, filter coatings and automated air filtering devices containing amorphous silica (natural diatomaceous earth).
2. Prior Art
The inventor has worked with diatomaceous earth for the past ten years. In 2009, he discovered characteristics of amorphous silica (natural diatomaceous earth) that makes it an excellent passive air filter material to eliminate indoor air pollution in various patentable embodiments. These characteristics, which are described herein, allow passive filters of amorphous silica (referred to in provisional patent application 61/335,316, “Adjacent Flow Passive Filters for Elimination of Indoor Air Pollution,” filed 2010 Jan. 5), to be utilized in the temperature pump cycle described herein. The reason for this name, “adjacent flow passive filters,” in provisional patent application 61/335,3316 was that the filters discussed therein were not placed in the stream of a moving gas, but rather adjacent to it, to allow the mineral matrix to attract pollutants into the filters for purification of the gas. Air (or more generally, the gas being purified) was not forced through the filters. Subsequent research by the inventor showed that amorphous silica may be used both in designs in which the filters are adjacent to the air flow, and in designs for which the amorphous silica filter is actually in a slow air flow leaking through the mineral, drawing out pollutants by osmosis (See “Temperature pipe” section of provisional patent application Ser. No. 61/342,284, “Automated Temperature Pumping Devices,” filed 2010 Apr. 4. Accordingly, the inventor has renamed the passive filters subject to this patent application the “temperature pump passive filters” to cover both design possibilities.
Further, as taught in provisional patent 61/342,284, “Automated Temperature Pumping Devices,” filed 2010 Apr. 4, also by the present inventor, the inventor has developed non-obvious, original automated devices using temperature pump passive filters. The subject automated temperature pumping devices use several different embodiments of temperature pump passive filters to adsorb pollutants out of an enclosed air volume into amorphous silica powder at a low temperature (less than about 26-27° C.). Subsequently, these devices (through a variety of means) increase the temperature of the pollutant-filled amorphous silica powder, increasing Brownian motion of the amorphous silica and the pollutant molecules within it, causing the amorphous silica to desorb the pollutants, thereafter venting them into the atmosphere.
The first public use of temperature pump passive filters (previously “adjacent flow passive filters”) for elimination of indoor air pollution began on Apr. 14, 2009. Provisional patent application 61/335,316 was filed by the inventor on 2010 Jan. 5.
Natural diatomaceous earth (amorphous silica) should be distinguished from other desiccants, in that it is a weak desiccant, forming a weak bond with water and other pollutant molecules under 26-27° C., which bond can easily be overcome by Brownian motion at temperatures over 26-27° C. Its transition temperature from adsorption to desorption thus lies just above room temperature (20-25° C.). This transition temperature is a critical element of the embodiments of the temperature pump passive filters and automated temperature pump device embodiments discussed herein.
In air, at temperatures less than the transition temperature, amorphous silica acts as a weak desiccant, and adsorbs gasses and micro-droplets of water containing a wide variety of small particulates (which serve as the nucleating agents for those micro-droplets) from the air. The nucleation agents have primarily positive charge, which attracts water molecules having a net negative charge. Thus, in humidified air, each pollutant particle immediately starts drawing a coating of water particles along with it. Amorphous silica attracts water molecules and other pollutants in a gas in a low temperature range, from at least −46° C. (probably lower, but experiments have only been conducted down to this temperature) up to about 26-27° C.
The concepts discussed in this regular patent application apply to pure natural diatomaceous earth (amorphous silica) of various grades of fineness. While the embodiment of the filters discussed herein could use calcined diatomaceous earth (a carcinogen), the inventor specifically sought out natural “food grade” diatomaceous earth with very low Cristabolite content (non-carcinogenic), to replace prior art humidity control filters based on calcined diatomaceous earth, and would not want to be responsible for patenting devices based on a carcinogen. Using calcined diatomaceous earth for these inventions would expose both manufacturing personnel and consumers of products made on the basis of these inventions to a dangerous carcinogen.
Any references to air herein should be understood to include other gasses which may be passively filtered with amorphous silica. It should be clear that the temperature pump cycle identified herein works with amorphous silica in various gasses, to attract a huge variety of contaminants, and in various temperature ranges, from extremely cold temperatures to approximately 26-27° C. The temperature pump passive filters and automated temperature pump device embodiments discussed herein are not intended to be limiting, but to be illustrative, and to support the author's patent claim to those non-obvious temperature pump passive filter embodiments and filter coatings, as well as to automated temperature pump device embodiments utilizing amorphous silica in the temperature pump cycle.
Function of Temperature Pump Passive Filters in a Gas
One can think in terms of partial pressures of gasses or adsorbable contaminants in air to understand the attraction of amorphous silica for those gasses or contaminants. The numerous adsorbent cavities in amorphous silica start out having effectively zero partial pressure of any gasses or contaminants, other than the gas in which it is immersed (in this case, air). When other gasses or contaminants which can be adsorbed by amorphous silica are introduced into a closed air volume in which amorphous silica is present, an attraction vector is set up toward the amorphous silica, because of the gradient of greater to lesser partial pressure which is established.
As the mineral adsorbs greater and greater numbers of molecules or small particulates, the partial pressure of each of these in the mineral gradually approaches their partial pressure in the closed air volume, until the attraction vector is decreased, and finally eliminated. The temperature range for amorphous silica's attraction of contaminants in air (at least −46° C. to about 26-27° C.) is important, because the mineral can only attract gasses or particulates when the Brownian motion of the pollutants is small enough for them to be retained within the mineral.
The in-stroke part of the temperature pump cycle occurs within this lower temperature range, at which the mineral adsorbs water micro-droplets and other molecules or groups of molecules having a higher partial pressure in air into the adsorptive surfaces of its diatoms.
Because of the water molecule's design, in confined regions the water molecules can more readily escape the adsorptive traps when the partial pressure of water gas (the Relative Humidity) outside the filter decreases, than can the pollutants, which originally served as the nucleation agents for the water micro-droplets. Water's tetrahedral design (a Y for which two of the legs may squeeze together, allowing the molecule to escape from tight spaces) may well explain why it can escape from confined spaces more easily than, say, odor molecules, viruses, airborne bacteria, mold spores, hyphal fragments, insect fragments or pollutant gas molecules in the same temperature range. Because of this effect, water more easily desorbs from amorphous silica than do the other pollutants when the relative humidity outside the amorphous silica decreases, even though the temperature remains in the adsorption range.
While the amorphous silica remains in the low-temperature range described above, the pollutants are stored in the temperature pump passive filter. This is the storage part of the temperature pump cycle. Because of its porous crystalline structure, amorphous silica has a great ability to adsorb and store large numbers of pollutant particulates and/or molecules.
Amorphous silica desorbs both water molecules and small particulates at temperatures above about 26-27° C. for the temperature pump cycle out-stroke, due to the increased Brownian motion of the molecules adsorbed into the amorphous silica and the Brownian motion of the amorphous silica (Si2O) molecules themselves. This temperature represents the approximate transition temperature from adsorption to desorption for amorphous silica in air at sea level, and can vary due to atmospheric pressure and viscosity of the specific medium in which the amorphous silica is located.
As stated above, the key to the temperature pump cycle concept is that water micro-droplets and other air pollutants only make a weak adsorbent bond to the amorphous silica, which Brownian motion can easily overcome at higher temperatures. This allows devices to be designed which use this pumping mechanism to cleanse air (and other gasses) of excess humidity and many other pollutants for a number of beneficial purposes.
Amorphous silica also adsorbs an extremely wide variety of pollutant gasses from an enclosed air space. As previously mentioned, microscopic spaces in amorphous silica initially have zero partial pressure of whatever pollutant may be present, so an attraction vector is set up, attracting the pollutant gas molecules to be adsorbed into the matrix structure of the amorphous silica. Because of amorphous silica's great inner storage capacity for gas molecules, a number of pollutant gasses can be reduced to undetectable levels in the room air for extended periods of time when a sufficient mass of amorphous silica is present. Tests for ethylene gas, chlorine gas and acetic acid molecules have been conducted. With temperature pump passive filters at work protecting a room, many small particulates and pollutant gasses can be virtually eliminated within the enclosed air space.
This regular patent application discloses embodiments of stationary amorphous silica temperature pump passive filters and filter coatings for use in eliminating excess humidity, small particulates and pollutant gasses from indoor air. Additionally, it discloses automated devices using temperature pump passive filters, discussed below.
Automated Devices Using Temperature Pump Passive Filters
As buildings have gotten more and more tightly designed to minimize air leakage and energy use for heating, ventilation and air conditioning (HVAC), indoor air pollution has become a greater and greater threat to the health of persons working or residing in those buildings. Bacterial diseases such as Legionnaire's disease (Legionella), MRSA and gas gangrene (Constridium perfringens) have become of great concern in public accommodations and hospitals. This regular patent application addresses new and unique ways to successfully eliminate excess humidity and/or indoor air pollution, including all of the species of airborne bacteria, molds, funguses, viruses and other pollutants, including various gaseous pollutants, listed below. Additionally, the broad-band attraction of amorphous silica for pollutants in air means that this regular patent application applies to the adsorption of any such pollutant particles or molecules present in the air (or gas) being purified. The automated temperature pumping device embodiments disclosed herein are devices which use amorphous silica passive filters (see Provisional Patent Application 61/335,316) to attract air pollutants and adsorb them into the mineral matrix of amorphous silica at temperatures below 26-27° C. (about 80° F.). This temperature is hereinafter referred to as the “transition temperature” for amorphous silica. The automated temperature pumping device then recycles the filter by closing the air intake from the indoor air, opening an outlet to the outdoor air, and heating the amorphous silica filter to desorb the pollutants when the temperature of the amorphous silica rises above the transition temperature. Accordingly, the filters need no replacement, unless the filter bag material becomes soiled due to long-term use, or unless the mineral itself becomes permanently polluted by some heavy pollutant load (such as by sticky hydrocarbons). In practice, the currently used temperature pump passive filter bag material has gotten soiled in a number of applications, but the mineral has never to the inventor's knowledge become so soiled as to become ineffective in its air-cleansing role. Molds, pollens, bacteria and funguses have not been observed growing in the amorphous silica powder. It may, however, be advisable to change filters annually to avoid even the possibility of contamination.
The automated temperature pumping device embodiments disclosed herein fall into two categories:
The temperature pump, in which excess humidity, small particulates and pollutant molecules at a temperature of less than about 26-27° C. are drawn by diffusion into a filter bag filled with amorphous silica in a cavity exposed to the indoor air volume being purified; then the port allowing indoor air access to the filter is closed, a port allowing the filter access to the outdoor air is opened, and the filter bag is heated to a temperature above the transition temperature of 26-27° C., allowing the excess humidity and air pollutants to desorb from the filter into atmospheric air;
and:
The temperature pipe, in which a temperature gradient is established in a pipe containing a filter bag of tightly packed amorphous silica, so that the temperature higher up in the pipe is sufficient to desorb excess humidity, small particulates and pollution molecules out of the pipe into the atmosphere, creating a “draft” of excess humidity, small particulates and pollution molecules upward from the lower part of the pipe, which remains at a temperature cool enough to attract excess humidity, small particulates and pollution molecules out of the indoor volume of air being purified.
Key to the temperature pump cycle concept is that water molecules and other air pollutants make a weak adsorbent bond to the amorphous silica at lower temperatures, which Brownian motion can easily overcome at higher temperatures. Thus a temperature pump makes it possible to “pump” excess humidity, particulate pollutants and gaseous pollutants into the amorphous silica matrix at low temperatures, and “discharge” the humidity and pollutants at a higher temperature. This allows devices to be designed which use this pumping mechanism to cleanse air (and other gasses) of excess humidity and many other pollutants for a number of beneficial purposes.
As detailed above, the inventor has found that the capacity of amorphous silica for many types of pollutants, both particulate and gaseous (including water vapor) is remarkable. Passive filters utilizing amorphous silica powder in a melt-blown filter cloth enclosure can be compared to attaching a gigantic tank full of perfectly clean air to an indoor volume of air-conditioned air. Osmosis carries virtually all of the indoor air pollution (and much excess humidity) into this passive filter “tank” while the “tank” is cool, below the transition temperature. However, if the “tank” is heated above the transition temperature, all the particulate and gaseous pollutants (including excess humidity) are discharged out of the “tank.” If the “discharge pipe” for this “tank” releases the humidity and pollutants to the outside air, the indoor volume of air that is cleaned typically ends up much cleaner than the outside air. Brownian motion in the heated mineral flushes out pollutants and water molecules in the mineral, restoring the “tank” to its perfectly clean state, capable once again of adsorbing excess humidity and both gaseous and particulate pollutants, down to 0 parts per billion for some pollutant gasses, and down to nearly 0 spores/m3 for fungal and bacterial spores.
Extensive experimentation described in preliminary patent application Ser. No. 61/335,316 and Ser. No. 61/342,284 using the temperature pump cycle with the temperature pump passive filters and automated devices described therein, achieved remarkable cleansing of indoor air pollution, including elimination of at least the following:                excess humidity (water vapor)        ethylene gas        chlorine gas        acetic acid molecules        other acid molecules        objectionable odors        ascospores        aspergillus spores        penicillium spores        basidiospores        cladosporium spores        stemphylium spores        most of the total fungal spore count        mold spores        airborne bacteria in general        small hydrocarbons, viruses and prions (by inference from experimental results)        pollens        hyphal (mold) fragments        insect fragments        dust and dust mites        
The results of the inventor's experimentation indicate that the nucleation agents around which water micro-droplets form, such as the above list of fungal spores, airborne bacteria, pollens, hyphal fragments and insect fragments, are adsorbed and trapped in the amorphous silica mineral interfaces at temperatures under about 26-27° C. (about 80° F.) until the temperature increases beyond that transition temperature. Larger particulates, such as pollens, are attracted to the surface of the amorphous silica particles, or to the filter enclosure material. Above that temperature, Brownian motion dislodges the water molecules, captured nucleation agents/pollutants (such as the above bacterial spores, mold spores and fungal spores), odors and pollutant gasses, allowing them to float freely into the surrounding air. Since viruses are known to be nucleation agents for both ice crystals and micro-droplets of water, the inventor's research indicates that very small nucleation agents, such as prions and viruses are also adsorbed by temperature pump passive filters. The fact that amorphous silica also attracts and retains small molecules such as water (H2O), ethylene gas (C2H4), chlorine gas (Cl2), and acetic acid (CH3COOH) argues that viral particles between the size of the above molecules and the size of larger biological particulates (such as spores and airborne bacteria) are adsorbed.
Many temperature pump passive filters are not placed in the stream of a moving gas, but rather adjacent to it, to allow the mineral matrix of amorphous silica to attract pollutants into the filters. Calcined diatomaceous earth functions well in such filters, but calcined diatomaceous earth is a carcinogen, whereas natural diatomaceous earth is non-carcinogenic. As a result, “food quality” amorphous silica is the filter material exclusively referred to in this regular patent application,
In some uses (see temperature pipe section below), temperature pump passive filters may be placed in a slow flow of air and pollutants. However, the slow flow of pollutants (and a little air) goes directly through tightly packed amorphous silica, being drawn by a diffusion gradient which is created by a temperature differential in the mineral. The pollutants and air are not forced through the filter by high air pressure.
The temperature pump cycle can be effectively utilized by the use of the new designs of temperature pump passive filters detailed below for the specific new purposes enumerated. The following provides a discussion of the prior art, followed by a detailed discussion of how new designs (and new uses) of temperature pump passive filters differ from the prior art in new and non-obvious ways, and thus are patentable.
As opposed to other filter concepts, such as the filter discussed in U.S. Pat. No. 4,824,450 (Howard), the amorphous silica filter (and other mineral filters using the temperature pump cycle) does not provide for high pressure air flow directly through the filter material. The aforesaid patent uses an air flow directed through filter bags formed of HEPA paper to actively filter out particulates by directly catching them in the HEPA paper matrix. This builds up a “cake” of particulates on the catch side of the filter, and ultimately decreases air flow with the blockage of the filter. The temperature pump passive filters function at a low temperature (below about 26-27° C.), not directly in a high pressure air flow, to attract micro-droplets of water and their nucleation agents—the particulates the filters adsorb and store. Since the filters are not in the direct flow of high pressure air, they do not block the air flow, and do not build up a caked layer of particulates. In designs of the temperature pump passive filters (See “Temperature pipe” section below) that provide for direct pollutant and air flow through the filter material, the slow flow of pollutants (and a little air) goes directly through tightly packed amorphous silica, being drawn by a diffusion gradient which is created by a temperature differential in the mineral. The pollutants and air are not forced through the filter by high air pressure.
U.S. Pat. No. 4,604,110, (Frazier) provided for filter elements containing a mixture of silica gel, activated charcoal and zeolite. Such a mixture would make the temperature pump cycle as described in this regular patent application inoperable, since the temperature pump cycle defined herein operates close to room temperature, with only moderate heating of the filter element required. Activated charcoal and zeolite have transition temperatures too high to allow cleansing of the filter material by solar heating, or by mild heating due to a heating element or heating jacket. For example, zeolites must be dehydrated at temperatures between 100° C.-300° C., compared with the effective desorption of water and pollutant molecules starting just above 26-27° C. for amorphous silica. The key to the temperature pump passive filter design is reusability. Such high drying temperatures would not be consistent with reusing the filters as designed. Similarly, the key to the automated devices using the temperature pump passive filters is the ability to recycle the filters (with only mild heating) through repeated cycles of adsorption and desorption of water molecules, particulate pollutants, and pollutant gases and molecules. Use of zeolites or activated charcoal would make recycling of the filter material impossible with the designs disclosed herein. A further distinction of temperature pump passive filters from the fan-driven filtration system in U.S. Pat. No. 4,604,110 is that temperature pump passive filters require no fan or other electrical motor or pump to force air through the filters, but rather, they use osmosis to effect gradual, but very complete filtration of indoor air.
U.S. Pat. No. 4,337,276 (Nakamura et al) disclosed a storage container containing freshness keeping agents for vegetables and fruits, consisting essentially of a particulate composition which contains at least two components selected from the group consisting of zeolite, bentonate and activated carbon. The freshness keeping agent absorbs ethylene gas, etc. generated from vegetables and fruits, thereby preventing them from over-ripening, softening, etc. Again, use of zeolites and activated carbon negate the use of the temperature pump cycle at temperatures near room temperature. Amorphous silica can achieve similar success in adsorbing ethylene gas, but operates in a moderate temperature range that allows the temperature pump cycle as described herein to cleanse filters using amorphous silica as a filter material.
U.S. Pat. No. 2,231,768 (Seibert, et al.) disclosed a five-stage air purification system which uses an air compressor to blow compressed air through (1) and oil and water coalescer filter; (2) an adsorbent or desiccant dryer; (3) and oil vapor adsorber; (4) an after-filter; and (5) a bacterial-retentive final filer. This design is completely different from the present regular patent application in the following respects: (1) The temperature pump passive filters do not have compressed air blown through them; rather, the amorphous silica in the passive filter is allowed to attract in the pollutants through osmosis, a much more gradual, and more effective filtration process which allows the filtration of the very smallest and most unhealthful pollutants present in the air; (2) the amorphous silica is used as a passive filtration agent for all pollutants in the temperature pump filter designs, while U.S. Pat. No. 2,231,768 utilizes activated silica gel only as a possible desiccant, to remove water and hydrocarbons (not other pollutants), and relies on other filtration agents which block the high-speed flow of the air to remove pollutants; (3) The temperature pump filtration cycle requires no motors or other air pumps to move the air to be filtered. This means that near-perfect air purification is achieved with no electric power being expended in moving the air—a major utility-saving feature; (4) The temperature pump designs disclosed herein do not have the disadvantage of having compressed, high speed air picking up particles of amorphous silica and possibly discharging them into the purified air. U.S. Pat. No. 2,231,768 takes special precautions (further slowing down airflow) to prevent desiccant particles from entering the purified air; (5) The temperature pump filter designs disclosed herein are all completely reusable with the application of a minimum amount of natural (solar) or other heating. U.S. Pat. No. 2,231,768 makes no mention of reusability of filters, and from the design it may be inferred that its filters are designed for one-time use.
The disclosed designs of temperature pump passive filters make the entire volume of the mineral contained in the filter available for adsorption of pollutants, not just the surface as in a HEPA filter. The stationary filters are generally placed adjacent to the air flow, and gradually attract pollutants into the mineral matrix. A caked layer does not generally appear on the outside of the filter. More pollutants are adsorbed into the large mass of the filter material instead.
Patentable embodiments of different types of passive air filters using the temperature pump cycle are designated as the temperature pump passive filters in this regular patent application.
Another benefit of temperature pump passive filters is that very small particulates ranging down to the size of viruses can be adsorbed, because they are attracted into the mineral matrix that effectively holds them until the temperature increases, allowing them to escape. HEPA filters must allow smaller particles through the paper matrix, because filter pores small enough to catch very small, sub-micron sized particles do not allow adequate air flow through the filtering material.
Prior art not originated by the inventor, but used by the inventor and others for humidity control for more than one year prior to this regular patent application, includes:
Small, home refrigerator and commercial reach-in refrigerator filters, having an inner cloth filter bag to contain the mineral, and either a plasticized cardboard box with holes cut in it to allow air access, or a plastic exterior container with holes in it to allow air access. The container is held to the wall of the refrigerator with adhesive hook and loop strips. The mineral used was calcined diatomaceous earth (which is carcinogenic), containing up to one-third marble dust by weight.
Filters with a filtration bag containing approximately one kilogram of calcined diatomaceous earth (carcinogenic), surrounded by a plastic clamshell, made up of an outer and inner shell, which connect into each other by means of formed plastic snaps. The entire assembly slides into a metal or plastic bracket screwed to the ceiling or wall of a refrigerator or freezer.
These calcined diatomaceous earth filters were used for the purpose of absorbing humidity, drying the refrigerator, extending the life of produce, and eliminating odors. They were not used for the purpose of adsorbing airborne particulate pollutants, spores or bacteria in air-conditioned or refrigerated spaces. These possibilities were unknown at the time of their use. Furthermore, they utilized a mixture of carcinogenic calcined diatomaceous earth and marble dust, not pure, non-carcinogenic natural amorphous silica, as do the new filters developed by the inventor.
The manufacturer of these products did not produce non-carcinogenic products suitable for large commercial application, such as in refrigerated warehouses or freezer warehouses.
When the inventor learned that calcined amorphous silica (the previously used mineral) is classed as a carcinogen in California, he experimented with pure amorphous silica (natural diatomaceous earth) in the place of the calcined product. Pure amorphous silica is non-carcinogenic. He found that amorphous silica has superior qualities of adsorption, and replaced his existing passive filtration media with it.
The inventor originated and tested large bag filters of pure amorphous silica (not calcined diatomaceous earth), and discovered that it is more than twice as efficient at adsorbing water and pollutant molecules as the previously utilized material. It adsorbs 116% of its weight in water, compared to 53% for the previous material. Added to this, it is non-carcinogenic and certified for use in food preparation areas. These initial filters were intended to serve refrigerator or freezer warehouses. These filters contain approximately 2 kilograms of pure amorphous silica (non-calcined) powder (a much less dense powder than the calcined diatomaceous earth and marble dust mixture previously utilized) in an inner filter bag of polypropylene filtration material, surrounded by an outer bag of rough protective cloth, and having two steel grommets for hanging. See FIG. 1 (The first use of such large bag filters for the purpose of adsorbing indoor airborne particulates and pollutants occurred on 2009 Apr. 14. PPA 61/335,316 was filed by the inventor on 2010 Jan. 5).
These filters provide a greater quantity of amorphous silica for lowering humidity, eliminating odors and saving electricity. However, they have the following drawbacks:                They are sewn together, and cannot be opened to change outdated mineral or to allow the bag to be cleaned.        They have steel grommets for hanging. These grommets rust and lose strength in the wet environments we serve.        If a bag became soiled, it has to be discarded. This is wasteful and against the recycling ethos of our company.        These filters have only two layers: An outer protective bag which could not contain the fine amorphous silica dust if the inner bag were somehow punctured, and the inner filter bag. There were a number of instances in which the inner filter bag developed a slight puncture and lost a significant amount of mineral.        
The fact that amorphous silica also directly attracts and adsorbs a wide variety of fungal spores, a wide variety of bacteria, a wide variety of pollens, hyphal fragments, insect fragments and feces, and a wide spectrum of other air particulates and pollutant gasses was not proven until the inventor conducted extensive experiments to prove these functions. This information itself is not patentable, but the application of the inventor's prior design (See FIG. 1) to this new purpose is patentable. Further, the new embodiments of temperature pump passive filters, filter coatings and automated devices using temperature pump passive filters, which are disclosed in this regular patent application, and which incorporate these functions in new and unobvious ways, are patentable.
The process underlying the humidity control function of the prior art products, the temperature pump cycle, was previously not understood as a general physical process which can be adapted to numerous embodiments for many different air filtering applications. The new, non-obvious, patentable embodiments described herein are all based on the temperature pump cycle.
Temperature pump cycle: This regular patent application applies to all the new designs of passive filtration devices shown herein using the concept of a “temperature pump cycle,” which utilizes amorphous silica for passive fluid filtration in a gaseous environment. Within a temperature range specific to amorphous silica in air or other gasses, the mineral draws in water micro-droplets, including the particulates which serve as the nucleation agents for these droplets. These nucleation agents include a wide variety of mold and fungal spores, airborne bacterial spores, pollens, viruses and other small particulates which are allergens or disease vectors. In a lower temperature range, these particulates are adsorbed by the amorphous silica. At a higher temperature, starting at a point referred to as the transition temperature (about 26-27° C.), the particulates are dislodged from the amorphous silica by Brownian motion, and are desorbed into the surrounding gas. The temperature pump cycle is based on the aforesaid process, by which the amorphous silica adsorbs and desorbs small particulates as a function of temperature.
Temperature pump passive filters are designed to operate passively in the cool environments into which they are placed, to be withdrawn periodically, and to be placed in a warm, drying atmosphere (or warmed with microwaves) to allow ex-filtration of humidity, pollution particulates and gasses into a drying facility air space where humidity and pollution are not a concern. These extremely useful and surprisingly revolutionary passive air filters are discussed in the following section to allow the Patent Office to evaluate a number of the different new applications of such filters. Already within less than 12 months of first public use (starting Apr. 14, 2009), the inventor has created a viable business of indoor pollution control with a number of customers.
This regular patent application describes the following embodiments of patentable temperature pump passive filters which permit practical use of the temperature pump cycle as described above. Most of these involve a specially designed filter which functions in a low-temperature, air-conditioned or refrigerated environment, which is withdrawn from that environment to be placed in a higher-temperature drying environment to allow humidity and nucleation pollutants to escape from the filter. However, some of the temperature pump passive filters will serve such sensitive environments (such as hospital laboratories and electronic clean rooms) that they are designed as disposable filters, not to be recycled like the majority of the designs discussed below. In the case of temperature pump passive filters, the use of existing designs of air filters in refrigerators and freezers is not the patentable design, since the inventor and others have been using such filters for a number of years for the limited purposes of better preserving food in refrigerators, preventing mold, saving energy and preventing icing in freezers.
Rather, the first claim category herein involves the use of stationary temperature pump passive filters comprising pure amorphous silica and various filter structures as anti-pollution devices, for the adsorption of a wide variety of spores, bacteria, viruses, insect parts, hyphal parts, pollens, other allergens, radon gas, and other air pollutants, both gaseous and particulate. The embodiments which follow are only exemplary of this general claim, and should not be considered as limiting the claim to these designs alone.
The second claim category of temperature herein comprises coatings of building material surfaces or a matrix of fibers with amorphous silica and an odorless, non-polluting adhesive to permanently control humidity and prevent condensation of water in a closed volume of air, in which high humidity or water condensation is undesirable, and which coating operates naturally to release the stored water molecules at a time when the relative humidity is low. These coatings also adsorb the pollutants listed in the above paragraph, specifically adsorbing and sequestering mold and other fungal spores which have become an increasing concern in tightly constructed buildings. The embodiments which follow are only exemplary of this general claim, and should not be considered as limiting the claim to these designs alone.
The third claim category involves automated devices which use temperature pump passive filters comprising pure amorphous silica and various filter structures as anti-pollution devices, for the adsorption of a wide variety of spores, bacteria, viruses, insect parts, hyphal parts, pollens, other allergens, radon gas, and other air pollutants, both gaseous and particulate. The embodiments are the “temperature pump” and the “temperature pipe”. The embodiments which follow are only exemplary of this general claim, and should not be considered as limiting the claim to these designs alone.
The problem with simply using amorphous silica as a passive filter material is obvious: Passive filters must be replaced when they become filled with pollutants. Using temperature pump passive filters for elimination of indoor air pollution assumes that these filters are changed out regularly, with the filters being thermally dried and allowed to discharge their pollutant loads to the atmosphere. The required change-out frequency ranges from one change-out every three months for light pollution loads (such as for household air conditioning applications), to change-outs once a week in heavy pollution applications (such as in a mushroom-growing facility choking with mushroom basidiospores and various fungal pest spores such as aspergillus, penicillium and verticillium). The requirement for filter change-out makes the use of temperature pump passive filters non-economic in some applications. This demands that automated designs for the use of amorphous silica's unique adsorption of excess humidity and air pollutants be developed to complement the many uses of stationary filters. This regular patent application presents patentable embodiments of temperature pump passive filters which require periodic change-out, as well as permanent adsorptive coatings of building materials for some functions, and embodiments of the temperature pump cycle that are automated, and thus do not require frequent filter change-out.
As regards the automated devices disclosed in Embodiments #21 through #27, the inventor's patent search has not revealed existing applications of amorphous silica automated temperature pumping devices (including the temperature pump and temperature pipe embodiments shown herein), other than his own. Automated temperature pumping device embodiments disclosed herein have not yet been used publicly by the inventor. The inventor has used temperature pump passive filters for the purpose of eliminating indoor air pollution for less than one year, and has made a successful business of doing so, but automated equipment for using amorphous silica's many positive characteristics for all purposes is clearly needed.
As briefly described above, the automated temperature pumping device embodiments fall into two categories, disclosed herein:
The temperature pump is a device which requires active heating of the filter body and concomitant release of pollutants into the atmosphere.
The temperature pipe embodiment may be totally passive, using solar heating of the pipe to accomplish cleansing of indoor air, or may be assisted by an active heating device. The temperature pipe may allow a small amount of indoor air to escape by flowing through the mineral powder, but since the filter in this embodiment completely blocks the pipe, and extends a good way up the pipe, very little air is lost.
Both of these major types of automated temperature pumping device embodiments are capable of cleansing indoor air to a much cleaner state than the outside air. Even after review of the “tank” discussion above, this fact may not seem obvious, since the temperature pump passive filters used in the temperature pump embodiments, and the filters used in the temperature pipe embodiments would initially appear to be mere conduits for osmosis of indoor pollutants to the outside air. If this were the case, the indoor air could only be cleaned to the often very polluted level of outdoor air, since no osmotic pressure would exist to allow more indoor pollutants to escape if simple osmosis were occurring. The key to amorphous silica's ability to cleanse indoor air to very pure states is that when the amorphous silica is raised above the above transition temperature, increased Brownian motion cleanses the mineral to a quite clean state, almost entirely free of all pollutants. Thus, gaseous and particulate pollutants are discharged from the heated mineral, even into outdoor air which is more polluted than the indoor air from which the pollutants were drawn. This requires a net input of energy, and the process is driven by the heat source which heats the mineral and increases the Brownian motion of the pollutants to discharge them, cleansing the filter.